My 12 year old dog was diagnosed with mast cell cancer over a year ago. She had surgery to remove one mast cell tumor which went well but the cancer soon returned with several more tumors. The cancer vet said it was inoperable so we turned to chemo and other cancer treatments to no avail. The cancer vet said to try the K9 Immunity Plus but didn't give us much hope. Well, my dog is still with us and has a good quality of life. Her appetite and energy have returned. You wouldn't know she has cancer. She still has the tumors but are not bothering her. In addition to this product, I started her on Pet Wellbeing Life Gold. Don't know which product is helping more but I will not stop either of them, Also, iherb has the best price on this product!!